| Project/Area Number |
20244065
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Atomic/Molecular/Quantum electronics
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| Research Institution | Japan Atomic Energy Agency |
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Principal Investigator |
BULANOV Sergei Japan Atomic Energy Agency, 量子ビーム応用研究部, 客員研究員 (00391318)
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| Co-Investigator(Kenkyū-buntansha) |
KANDO Masaki 日本原子力研究開発機構, 研究副主幹 (50343942)
ESIRKEPOV Timur 日本原子力研究開発機構, 研究副主幹 (10370363)
PIROZHKOV Alexander 日本原子力研究開発機構, 研究員 (00446410)
KAWACHI Tetsuya 日本原子力研究開発機構, 研究主幹 (40343941)
KIRIYAMA Hiromitsu 日本原子力研究開発機構, 研究副主幹 (40354972)
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| Co-Investigator(Renkei-kenkyūsha) |
KOTAKI Hideyuki 日本原子力研究開発機構, 研究副主幹 (60354974)
FUKUDA Yuji 日本原子力研究開発機構, 研究副主幹 (30311327)
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| Project Period (FY) |
2008 – 2010
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| Project Status |
Completed (Fiscal Year 2010)
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| Budget Amount *help |
¥48,360,000 (Direct Cost: ¥37,200,000、Indirect Cost: ¥11,160,000)
Fiscal Year 2010: ¥15,340,000 (Direct Cost: ¥11,800,000、Indirect Cost: ¥3,540,000)
Fiscal Year 2009: ¥11,960,000 (Direct Cost: ¥9,200,000、Indirect Cost: ¥2,760,000)
Fiscal Year 2008: ¥21,060,000 (Direct Cost: ¥16,200,000、Indirect Cost: ¥4,860,000)
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| Keywords | ビーム物理 / 高強度レーザー / レーザープラズマ相互作用 / 非線形ラングミュア波 / アト秒X線 / 水の窓X線 / 周波数上昇 / 高次高調波 |
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| Research Abstract |
We investigated a novel x-ray generation mechanism (relativistic flying mirror) using the nonlinear interaction of a high-intensity laser with plasma. In an underdense plasma, the laser excites a wake wave and form cusp density profile in the highly nonlinear regime. The cusp partially reflects a counter-propagating laser pulse in the form of X-rays due to the double Doppler effect. We implemented an experimental setup with two counter-propagating laser pulses interacting with the helium gas target. The observed reflected photon wavelength ranged from 12 nm to 20 nm, while the incident laser wavelength was 820 nm. The reflectivity in terms of photon number was 2×10^<-5>. This is close to the theoretical estimate, which proves the feasibility and efficiency of the flying mirror scheme. In addition, with a single laser pulse focused onto a helium gas target with a relativistic intensity, we observed in the forward direction a high-order harmonic radiation with unique properties. The harmonic extend to the 'water window' spectral region and contain more than 300 resolved orders. The harmonics with both even and odd orders of the same intensities are generated by both linearly and circularly polarized laser pulses. We propose a new mechanism of high-order harmonics generation that explains our experimental results. This mechanism is based on catastrophe theory, which predicts structurally stable electron density singularity formation inside the laser pulse. Computer simulations show the singularity formation and associated harmonic emission, in agreement with the experimental results.
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